How convert decimal to time

Question

I'm working with php and try to convert decimal to time(hh : mm) but it does not work with any code and tested, the original string is from excel eg:

0.625 = 15:00
0.53541666666667 = 12:51
0.40277777777778 = 09:40

Answer 1

I'd generally recommend using the DateTime class for any date arithmetic, rather than working it out manually. It'll take into account any daylight-savings/etc (although it's not clear from your question whether or not that would be desired).

<?php
/**
 * @param float $x Decimal number of hours
 * @return string HH:mm
 */
function dec_hours($x) {
    $sec = intval($x * (24 * 60 * 60));
    $date = new DateTime("today +$sec seconds");
    return $date->format('H:i');
}

echo dec_hours(0.625);            // 15:00
echo dec_hours(0.53541666666667); // 12:51
echo dec_hours(0.40277777777778); // 09:40

Answer 2

$dec = 0.625;

This is simple. To convert from decimals to hours, make a multiplication with 24.

$hours = $dec * 24;

Now to convert from decimals to hours:mins use this:

function convertTime($dec)
{
    // start by converting to seconds
    $seconds = ($dec * 3600);
    // we're given hours, so let's get those the easy way
    $hours = floor($dec);
    // since we've "calculated" hours, let's remove them from the seconds variable
    $seconds -= $hours * 3600;
    // calculate minutes left
    $minutes = floor($seconds / 60);
    // remove those from seconds as well
    $seconds -= $minutes * 60;
    // return the time formatted HH:MM:SS
    return lz($hours).":".lz($minutes).":".lz($seconds);
}

// lz = leading zero
function lz($num)
{
    return (strlen($num) < 2) ? "0{$num}" : $num;
}

echo convertTime($hours);

^{Source: How to convert a decimal into time, eg. HH:MM:SS}

Output: http://ideone.com/Q7lkwX